Method of repairing tire casings



Patented Feb. 28, 1933 UNITED STATES JOSEPH J. DETTLING, oF'nxRoN, 'o1-11o,

Assrenon, To man GENERAL TIRE sa RUBBER COMPANY, or AKRON, Onto, A conronnmron or OHIO :METHOD or mnnfi1-:eine 'TIRE casinos-2 Application 1ed'J111y..25, 1928. Serial No. 295,143.4

The present invention relates to method of repairing tire. casings and has foruits most important objects to provide avrepair of superior strength and durability, to `provide arepair which is economical of material and which may bemade at a relatively small cost and to providea repair; vwhich effects a saving in time and labor.

In repairing cuts, blow-outs andthe likeV in pneumatic tire casings, it has been "colmmon practice to cut away successive plies'of reinforcing fabric around the damaged portion at the interior of the casing to Kform a Astepped recess, and to fillin such recess with layers of fabric and raw rubber which are vulcanized in place. A Such 'patches have not been as strong or as durableas is desirable for the reason that the patches tend to work loose from the body of the casing.`

One of the main reasons for the failure of such patches is believed to be that the material of the patch when subjected continuously to road shocks and vibrations gradually becomes stretched until the patch has a greater area than the recess in the wall of the tire casing in which it is secured so thatthere is a tendency for the patch to wrinkle and forportions thereofl to slide upon the por? tions of the tire casing to which they are secured with the result that the union between the patch and casing is gradually loosened.

This diicultyris avoided in the present invention by the use of patches which have beenV cut from the fabric reinforced walls of used tire casings. The rubber of such patches has'been stretched or eXtendedtosubst-antially the same extent as that of the tires to be repaired so that there is `no danger of the patch stretching to asize greater than that of the recess in which it is'secured'.

Furthermore, the use of patchestcut from the old tire casings reduces the cost ofthe material used in the repair and effects con- ,siderable saving in time in making therepair,

since all of the plies removed from thetire casing around the damaged portion are replaced at onetime. It has also been lfoundA l The present invention also has for an Ob-` `ject, the provision' of a repair patchwhich is so shaped that road shocksv and vibrations have, little tendency to Vcause l separation of the patch from the tire casing.v

Bycutting a patch of such form that 4the ends thereof taper Vsubstantially to a point l" and by applying this patch to a tire casing with the pointed ends extending circumferentially of the tire casing, road shocks are received first upon the point of the patch and are gradually tapered oiftoward the center of the patch vso that abrupt tearing stresses lare not applied along Vany eXten'ded-edgeof the patch., Y ,Y p

Vlvith the above and other objects in view, the invention-may be said to comprisefthe method as illustrated in the. accompanying drawing hereinafter described and particularvly set forth in the appended claims, together with such variations 'and modications there-` of 'as will beapparent to one skilled in the art to which the invention appertains. Reference should be had to the accompanying `drawing of this specilication in which:

f Figure 1 isf a plan view `of a patch such as used in repairing the tire casing by. the methodgoflthe present invention. n Fig 2 is a plan view'of the interior of a Vtire casing prepared to receive the patch shown in Fig. 1. i

Fig. 3 lisa section through a completed tire repair. Y Y

Referring to the accompanying drawing, a tire patch cut'from a used tire casing is shown in Fig. and this patch consists of superpose-d plies l, 2, 3 and 4 which are cutV to substansoY tially diamond shape with the plies of proi -gressively smaller size toprovide steps along each of the edges ofthe patch. vt Infpreparing thetire'casing 5 to receive the patch, the patch is laid upon the interior of the tire casing over the damaged portion such asthe hole 6 shown in F ig.' 2 and the casing f is marked along the edges'of the patch to Vindicate the lines of cut for removing,v the inner ply. of the fabric around the damaged portion. A diamond shaped piece .corre- *nspondingin size to the outer ply 1 of t-hepatch -1s thus removed from the inner ply "7 Of-,the

tire casing. The next outer ply 8 is then cut along lines spaced inwardly from the edge of the opening of the outer ply corresponding to the space between the edge. of the ply 2 of the patch and the edge of the outer ply l vto provide an opening in the second Y ply 8 corresponding in size and shape to the ply 2 of the'patch. The next successive vplies 9 and l0 of the casing are then cut to provide openings therein corresponding vin size and shape to the plies 3 and 4lof the patch. Al

tapered recess is thus provided upon thein terior of the tire casing in which the tire patch d andiexteriorlyr of the-tire are thoroughly will fit. The tire casing outwardly of the reinforced fabric is skived at an angle of from '30 .to 45 .to provide a tapering recess from the .outer surface ofthe casing to the fabric reinforcement. n .1 Y ln preparing the tire casing for the repair,

the surfaces of the tapered recess interiorly cleaned land bufled. rlhe stepped edges of thefabric reinforcement of theV tire casing andpatch are then treated first with a relatively thin rubber cement and then with a heavier rubber cement. After the cement is thoroughly dry, the outer recess of the tire casing is filled with cushion stock gum 1l tol the interior cf the Vtread portion and with tread stock gum l2 to the outer surface of the tread portion. The tire patch is then applied in the inner recessesof the tire casing with va thin layer 13 of raw rubber interposed between the patch and the body of the tire cas-V ing. YA thin strip of raw rubber 14 is then yapplied to the interior surface ofl the tire v casing along the margin of the patchcovering the adjoining ledges Vof the outer ply l of the patch and the inner `ply 7 of the casing, the interior of theV tire casingand the outer sur'- face of the patches having been cleaned, buffe-d and coated with rubber cement along the edges to which the strip 14 is applied. The repair portion is then secured in a suitable press and vulcanized. f

In cutting the patch from'an old tire casing, the cuts forming the edges of the patch are preferably made parallel with and at substantially right angles to the cords ofthe fabric and in removing the fabric frointhe interior of a tire casing being repaired, the cuts are made in substantially the same. manner so that the patch may be fitted in the recess formed in the tire casing with the cords.

of successive plies of fabric of the patch eX- tending inthe same direction as the cords of the corresponding plies of the tire casing.

A repair made in accordance with the method of the present invention has great strength and durability'for the reason that the patch taken from an old tire casing will 'not stretch to any appreciable extent after it is applied and for thefurther reason that the pointed ends of the patch extending circumferentially of the tire receive road shocks lirst at the point of the patch and gradually distribute the shocks toward the center of the patch, there being no broad' edge directly presented to obstructions in the surface of the road and liable to be torn loose by impact against such obstructions.

The strength and durability of the patch is also greatly increasedby theapplication of the thin rubber strip coveringthe joint between -the patchfand'the body of the tire vcasing which prevents fraying of the edges andfgradual separation which would otherwise occur. n

It will also be apparent that the present invention effects considerable saving in the cost of making a repair, since'` the patch is made from scrapped tire casingsand since the entire patch mayl be made in one piece I softhat all the yplies are inserted simultal. The herein described method of repair-` ing pneumatic tire casings'which comprises cutting the inner plyof the reinforcingfabric'of the casingk around the damaged portion thereof to forman. opening in .said ply whichis elongated circu'mferentially of the tire casingand which tapers substantially to a point at both ends, two opposite sidesy of the opening being parallel to the cords ofthe ply fabricv and the other two sidesthereof extending substantially Aat right .angles-.to said cords, cutting similar .progressively smaller openings in successive pliesof the reinforcing fabricto form a` recesswith stepped sides, applying athin layer ofraw vrubber to the stepped lsides ofthe recess, and

vulcanizing in the recess `a tire patch havingsuperposed'pieces of reinforcing fabric formed to` fitin the openings of the plies lof reinforcing fabric of the casing.

2. The herein described method of repairing pneumatic tire casings which comprises vcutting .the inner ply of the reinforcing fab` ric;of the casing around the damaged portion thereof to form an opening in said ply which is elongated circumferentially ofthe tirel casing and which tapers substantially to a point at both ends, two opposite sides of the vopening being parallelto the cords of the ply fabric andthe other twoy sides there.- of extending substantially at right` angles `to said cords, cutting similar progressively smaller openings in successive plies of therecutting the inner ply of the reinforcing fabric of the casinof around the damaged portion thereof to Form an opening in said ply which is elongated circumferentially of the casing and Which tapers substantially to a point at both ends, tWo opposite sides of the opening being parallel to the cords of the ply fabric and the other two sides thereof extending substantially at right angles to said cords, cutting similar 'progressively smaller openings in successive plies of the reinforcing fabric to form a recess with stepped sides, applying a thin layer of raw rubber to the stepped sides of the recess, and vulcanizing in the recess a tire patch cut from a corresponding part of a used tire casing, and having superposed pieces of fabric reinforcement of a size and shape to it in the openings of the plies of reinforcing fabric of the casing, the cords of the reinforcing fabric of the patch extending in the saine f direction as the cords in the corresponding plies of fabric in the tire casing.

In testimony whereof I aiiix my signature.

JOSEPH J. DETTLING. 

